The Smallest Strategist of the Scout Regiment
by TheEndOfEverythingYouKnow
Summary: An accident in Hange's laboratory turns Armin into a six year old, both in body and in memory. Will the Scouts find a way to change Armin back, or are they in danger of losing their little strategist forever?
1. Chapter 1

**An accident in Hange's laboratory turns Armin into a six year old, physically and mentally. Confused and fighting to adjust, will the Survey Corps find a way to change Armin back, or will they lose their strategist forever?**

 **Just a little something I'm writing to get me back into the writing mood. Set sometime in the period between the cadets joining the Scout Regiment and the 57th Expedition, which I decided to make longer than a month for my own twisted purposes.**

 **Disclaimer: I do not own Attack on Titan (Shingeki no Kyojin) or anything else.**

* * *

Levi decided that there was no possible way for his day to get any worse.

The nightmare had begun earlier than usual, as, just before dawn, the Jaeger brat had decided to transform into a Titan in his sleep, which just about destroyed half of the castle that they were using as a base. Jaeger was also apparently unaware that he was awake, and proceeded to run around destroying things until Arlert got him to calm down.

Then, of course, Jaeger was so fiercely apologetic and Arlert defended him so well and Ackerman so determinedly refused to let anyone near him that Erwin let him off without punishment. And Levi was left to supervise the cleanup of Jaeger's mess.

Once they managed to clean the place up, after heavy incompetence on the part of the new recruits and numerous death threats from Levi, there was hardly any time for training, which everyone complained about, and he caught the Braus brat with stolen food again.

Then, Kirschtein and Jaeger got into an argument at dinner over who knows what and Levi had to physically rip them apart, which earned him a glare from Ackerman. Afterwards, Erwin announced plans for another expedition outside Wall Rose, which Arlert was supposed to go over with him. So, if anyone saw Alert, he was supposed to report to Commander Erwin as soon as possible. Levi was ready to lock himself in his room for the rest of the night and let the brats sort things out for themselves.

And so, just as everything was supposed to be settling down, there came the sounds of an explosion from Hange's lab.

No, the day could not possibly get worse.

Levi told everyone gathered around the entrance to the lab to step back before he pounded on the door.

"Hey! Shitty glasses! Open up! What are you up to this time? We've already had half the base blown off today!"

The door suddenly flew open just far enough for Hange's head to emerge. She peered around at everyone suspiciously before catching sight of Levi.

"Oh! Hello, Levi. I thought I heard you calling. What brings you all down here, huh?" Hange spoke rapidly, the usual grin on her face and excitement in her voice.

"We're here because you shook the entire castle, shitty glasses. Care to tell us why?" Levi put a hand on the door, prepared to force his way inside.

Hange tried to close the door. "Oh, nothing. Just my usual projects, nothing new in here, thank you, goodbye!"

"Can I talk to Armin, then?" Jaeger piped up, joining Levi in his attempts to get past Hange.

"Armin? No, he's not here right now. Why don't you go look for him somewhere else?"

"No!" Eren yelled, "I know he's in there! He took over for Moblit so he could get something to eat and he didn't come back! What have you done to him?!"

Hange decided to put more effort into closing the door than providing an answer, but the rest of the recruits chose that moment to help force the door open. Hange jumped back as everyone tumbled into the room.

The lab was in complete disarray. There was shattered glass on the floor, papers scattered everywhere, and a heavy mist in the air. Arlert was nowhere to be seen.

"See?" Hange said, gesturing to the mess with both arms and blocking the way into the aisles. "No Armin here, just a mess. Nothing to worry about. You should all just go and look for him elsewhere, and send Moblit to me if you find him."

"Then why don't you stop blocking the way and let us see what you're hiding down that aisle?" Mikasa Ackerman remarked, her voice low and cold.

Hange giggled nervously. "That's really not necessary."

Jaeger suddenly caught on. "What did you do to him?" He tried to rush forward, but Ackerman and Kirschtein held him back. Levi, on the other hand, proceeded to calmly walk around Hange and turn an apathetic glare between the long tables.

And he froze.

He just had to let himself think the day was over, didn't he?

"Hange," Levi drawled, for once struggling to remain calm. "What am I looking at here?"

Hange sighed and gave up trying to block the way. "I'm honestly not sure. I was trying to make a potion that would make Titans smaller, but Armin tripped on something and we sort of… accidently knocked a few beakers into each other. It really made a mess, huh?"

Jaeger broke free and rushed past Hange and down the aisle with a startled cry, Ackerman right behind him, to the tiny body on the floor.

Jaeger knelt next to the small form and gently rolled it over, finding himself staring at the unconscious, disheveled, much younger form of…

"Armin?!"


	2. Chapter 2

Eren stared at the small body in his arms. He didn't understand how this had happened, but he couldn't deny that this was Armin. He looked exactly the same as he had the day Eren had first met him, when they were both six years old. He was still in his Scouts uniform, however, which was now several sizes too big for him.

"We should take him somewhere else, Eren," Mikasa murmured, crouching down next to her adoptive brother and now little friend. "We don't know how much this could have damaged him, and you know if he wakes up surrounded by people he'll panic."

Eren nodded and carefully stood, holding Armin close to him. Mikasa went ahead of them, making a path through the crowd. Levi had dragged Hange off to explain the situation to Erwin, but the others had stayed, trying to see what had happened to the little strategist.

There were several gasps and audible curses as the others caught sight of Armin. Jean swore loudly and Connie laughed. Bertholdt was silent and Reiner scratched his head, dumbfounded. A few of the girls cooed at Armin's tiny sleeping face, but a glare from Mikasa stopped them from coming any closer.

As they exited the lab, Moblit came sprinting around the corner. He skidded to a halt when he caught sight of them.

"Oh no," he said, wide eyes landing on Armin. "I shouldn't have left him alone with Hange. This is all my fault!"

"Don't blame yourself," Eren said, "It was an accident. Just find a way to fix it."

Moblit sighed with relief. "I was afraid Hange used him as a test subject. But if it really was an accident… figuring out exactly what happened and how to fix it won't be easy. Excuse me…" The siblings let Moblit pass and hurried away before Moblit could order everyone out of the lab.

Armin stirred slightly and snuffled, his face contorted in pain for a moment, before he resettled with the side of his face pressed to Eren's chest. Eren fought against a sudden urge to cry.

"Hold on, Armin. It's gonna be okay."

* * *

The trio arrived at the large room that served as the base's medical wing. Eren reluctantly set Armin down on a bed while Mikasa checked the supplies in the cabinets. Armin responded to the sudden absence of Eren's warmth by whimpering and reaching his arms out, though his eyes remained closed. Eren's breathing hitched once again as he sat down on the bed and gently pulled Armin back to him. He still couldn't believe this was happening.

"Mikasa," the titan shifter said as he ran his fingers through Armin's soft golden hair, "What if they can't change him back? What if he's stuck like this?"

He heard Mikasa take a deep breath to stabilize herself. "Let's not worry about that right now, Eren. All we can do now is take care of him, so focus on that."

Mikasa approached the bed with a tray of supplies. "Help me undress him so we can look him over."

Eren blushed. "W-why do we need to do that?" he asked, turning his face away.

"We have to make sure he's not injured in any way, Eren. And calm down. It's just Armin." Mikasa smirked at Eren's embarrassment.

"Whatever," Eren grumbled, sitting Armin up against his chest and slipping the jacket off of his fragile shoulders. "I don't suppose anyone has any clothes that would fit him, huh?"

Mikasa slipped Armin's pants and harnesses off without needing to loosen anything. "We could check the nearest village, I suppose. He can't go around naked." Eren helped her unbutton Armin's white shirt, deciding to leave that and his underpants on until they found appropriate attire for him. Meanwhile, Armin hadn't so much as sniffled since Eren had picked him back up. Eren was glad he was sleeping soundly, but he was also worried about what he'd be like when he woke up.

They found few signs of physical damage on Armin's body, other than some minor cuts and scars. The cuts were from the flying shards of glass resulting from the exploded beakers. The scars, Eren bitterly told Mikasa, had been there for a while, though some of them had disappeared. It was strange, as though someone had turned back the clock to make Armin's body exactly as it had been at age six. What concerned Eren most, however, was how pale Armin looked. He hadn't been this pale since before they had started training, and then usually when he was ill.

Once Armin was all cleaned up, Eren buttoned Armin's shirt and tucked him in under the covers, laying next to him to keep him warm. Mikasa sat at the end of the bed and kept watch on the door, waiting for their superiors to eventually show up.

* * *

Levi dragged Hange all the way to Erwin's office and burst through the door without knocking. Commander Erwin dropped the file he had been holding and reached for something in his desk, but stopped when he realized who they were.

"Levi, Hange, what's going on? You were supposed to send Arlert up here. Is there some sort of trouble?"

Levi relinquished his hold on Hange and shoved the taller brunette forward. "You tell him," he grumbled.

Erwin cocked an eyebrow and folded his arms as Hange shifted from foot to foot. "Well…" she started, "Armin was helping me in the lab- we were working on the titan shrinking serum and a few other things- when something on the floor tripped him up. He crashed into me, I crashed into our project, a bunch of stuff mixed together and Armin pushed me out of the way before it exploded. I couldn't see anything, but when the fog cleared a bit I saw him on the floor, and…"

"And what?" Erwin said, expecting the worst.

"She's turned Arlert into a kid, Erwin," Levi said, shaking his head in disgust.

Erwin wasn't sure whether to laugh, shout, or just shake his head. He settled for sighing and pinching the bridge of his nose to hold back a headache. "As though we hadn't been through enough today…Where is Arlert now?"

"Jaeger and Ackerman have him," Levi said.

"They're probably in the hospital wing, checking the damage! Can I go see? Can I? Can I? He must be so cute, all tiny and sleepy and..."

Levi and Erwin just shook their heads. Suddenly, they heard a frantic knocking on the door, which Hange opened to reveal an incredibly flustered Moblit.

"Hange!" he cried, "This is a disaster! I asked you not to work on anything too dangerous until I got back, and now you've gone and turned Armin into a little kid! We can't have a kid running around with the Survey Corps! As though this weren't dangerous enough already-"

"Enough," Erwin commanded. "You've got a point there. This needs to stay quiet so we can get Arlert back to normal. This stays within the Scouts, got it? Hange, Moblit, find everyone who knows and swear them to secrecy. You can begin going through the lab and figuring out how to reverse this in the morning. Levi, you're coming with me to check up on Arlert."

"Oh!" Hange squealed. "Can't I see him, Erwin, please? We could run some tests on him, gauge his mental state, see if he really has de-aged or is just a smaller version of himself-"

"No, Hange," Erwin said, almost smiling. "That can be your punishment. No contact with Arlert until I say so. _If_ I say so." And with that, Moblit led a disappointed Hange out of Erwin's office and Erwin and Levi set off for the medical room.

* * *

Mikasa was watching Eren and Armin sleep when she heard footsteps approaching the hospital wing. Taking out a dagger, she stood and prepared herself to fight whoever dared pass through that door and attempt to harm her boys. Her posture did not alter in the slightest when the footsteps paused and someone knocked from the other side of the door.

"State your name and purpose," Mikasa demanded, her voice quiet and dangerous.

"It's Captain Levi and Commander Erwin. We're here to check on Arlert," Erwin stated calmly.

Mikasa unlocked the door and let them in, checking the hallway before sheathing the dagger and closing the door. "They're resting, so keep your voices down," she said, nodding to the bed.

Levi stayed near the door, but Erwin moved closer to examine the sleeping figures on the bed. "Has Armin awakened at all since the incident? Said anything?" he inquired, eyes focused on Armin's peaceful face.

"No. He became restless a couple of times but didn't wake. Eren and I checked him over and he doesn't appear to be harmed other than a few scratches, but Eren said some of his scars have disappeared." Mikasa had moved to a position that allowed her to see everyone in the room as well as the door.

"Scars?" Levi asked suddenly. "He hasn't even been on an actual expedition yet. Why is he scarred?"

Mikasa made a sound that Erwin and Levi would swear was a growl. "Armin's always been a target for bullies. Eren and I protect him when we can, but we couldn't always be there to stop him from getting hurt."

"Understood," Erwin nodded, "However, I'm guessing we won't be able to fully understand Arlert's situation until he can wake up and tell us himself. We'll let him stay in here until we have more information."

"Better move Jaeger, then," Levi said, walking up to the bed and shaking Eren's shoulder. Eren groaned and opened his eyes, sitting up and holding Armin tightly even once he recognized who had awakened him. "Come on, Jaeger, back to your cell."

Eren looked down at Armin. "Can't I stay here? What if he needs me?"

"What if you turn into a titan in your sleep again? You'll crush him and the other half of the base. Ackerman can stay with him tonight." Erwin and Mikasa nodded at Levi's suggestion and Mikasa returned to her chair by the bed. "Go on and rest, Eren," she said, "I'll look after him."

"Okay," Eren conceded, "But let me know the second he wakes up!" Eren then left for the dungeons with Levi following shortly after. Erwin gave Mikasa a final order as he left the wing:

"Let me know if there are any developments."

"Yes, sir," Mikasa nodded, locked the door behind him, and watched Armin's chest rise and fall until she too fell asleep.


End file.
